 /*******************************************************************************
  * Copyright (c) 2005, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  * Wieant (wieant@tasking.com) - Bug 138007
  *******************************************************************************/
 package org.eclipse.ui.externaltools.internal.variables;

 import java.io.File ;
 import java.util.Map ;
 import java.util.StringTokenizer ;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.variables.IDynamicVariable;
 import org.eclipse.core.variables.IDynamicVariableResolver;
 import org.eclipse.debug.core.DebugPlugin;
 import org.eclipse.ui.externaltools.internal.model.IExternalToolConstants;

 public class SystemPathResolver implements IDynamicVariableResolver {
     
     /* (non-Javadoc)
      * @see org.eclipse.core.variables.IDynamicVariableResolver#resolveValue(org.eclipse.core.variables.IDynamicVariable, java.lang.String)
      */
     public String resolveValue(IDynamicVariable variable, String argument) throws CoreException {
         if (argument == null) {
             throw new CoreException(new Status(IStatus.ERROR, IExternalToolConstants.PLUGIN_ID, IExternalToolConstants.ERR_INTERNAL_ERROR, VariableMessages.SystemPathResolver_0, null));
         }
         Map map= DebugPlugin.getDefault().getLaunchManager().getNativeEnvironment();
         String path= (String ) map.get("PATH"); //$NON-NLS-1$
 if (path == null) {
             return argument;
         }
         // On MS Windows the PATHEXT environment variable defines which file extensions
 // mark files that are executable (e.g. .EXE, .COM, .BAT)
 String pathext = (String ) map.get("PATHEXT"); //$NON-NLS-1$
 StringTokenizer tokenizer= new StringTokenizer (path, File.pathSeparator);
         while (tokenizer.hasMoreTokens()) {
             String pathElement= tokenizer.nextToken();
             File pathElementFile= new File (pathElement);
             if (pathElementFile.isDirectory()) {
                 File toolFile= new File (pathElementFile, argument);
                 if (toolFile.exists()) {
                     return toolFile.getAbsolutePath();
                 }
                 if ( pathext != null ) {
                     StringTokenizer pathextTokenizer = new StringTokenizer (pathext, File.pathSeparator);
                     while (pathextTokenizer.hasMoreTokens()) {
                         String pathextElement = pathextTokenizer.nextToken();
                         toolFile = new File (pathElementFile, argument + pathextElement);
                         if (toolFile.exists()) {
                             return toolFile.getAbsolutePath();
                         }
                     }
                 }
             }
         }
         return argument;
     }
 }

